The first SCP work i have done. Personality Separator. I think this is very good (for me at least), so i think it would be nice to have some critics in it. Remember: No physical contact allowed! Series IV

Hello, This is the start of my great SCP projects (maybe.. huh?), the first SCP i made is a Humanoid one (Be aware of it…)
I would really be happy if you guys could read and tell me if this is good, what can i change. Thanks you in advance!

I moved your thread description to the first post and trimmed it above, OP, since it was taking up a lot of space on the forum listing. Try to keep thread descriptions under 7 lines so you don't visually crowd out other people's threads. ~Zyn

Those are just two dimensions. Remember that we live in a 3 dimensional world!
Also, feet aren't nessecary. The Foundation rarely uses the imperial system.

Recreational devices are necessary to maintain its sanity, provided once every week.

What is a recreational device in this case? I tried looking it up, but all I got was some form of crossword or something. I think you should specify it a bit more.

No physical contact should be made with it without adequate equipment

What is adequate equipment? You've never specified what exactly they need to bring.

No personal

*Personnel

with personality disorder or extreme fertile imagination must come close to SCP-XXXX, even with the necessary equipment.

I mean, isn't that a given to all SCPs? You don't have to specify it, because you don't really want any personnel that may act unprofessionally around an SCP.

Because of its nature, nothing that can treat or scary SCP-XXXX can enter in its room (only if SCP-XXXX allows it)

*Threaten or scare
Also, you just said that nothing scary can enter her room! Why would you even state that she can allow it herself? Because I read the whole thing, and it would be really out of character from her.

SCP-XXXX is a 16-year-old girl, with red hair, pale skin, black eyes and very quiet.

"Very quiet" is not a physical trait. It's basically like me saying "I have a giant Mohawk, black skin, blue eyes and I really hate Mondays."

Any humans that have disorder problems or have extremely fertile imagination who make contact with this specimenl, get sick in a period of 1 to 3 hours and lose conscience.

…Well, then don't let them near her. This anomaly seems so easily avoidable.

After a period of 24 hours has passed, the second personality of the subject will appear nearby in a body of its own, unconscious and the subject will stop having the personality disorder or any signs of the sickness, regaining conscience again

I'll be honest, it was really hard figuring out what the anomaly was. Never mind the grammatical errors, I just don't know what you're getting onto. Here's what I've figured out:
It's able to somehow transfer itself over to another body, but it is only restricted to people that have personality disorders or fertile imaginations, correct? So it's basically a hive mind? Or is it simply a different personality? The whole thing was just really confusing.

The second person can be completely different from the original subject, being of another sex, with a different skin and hair tone, and with a complete different personality, problems and intelligence, but will retain some of the memories of the subject.

See, now it just gets really convoluted. When you mention subject, Are you talking about body or personality? Because you seem to split so much between those two, so I dunno which one you're talking about.

After that, the person affected by SCP-XXXX will not receive any more effect by its ability again, making its ability one use per person.

Wait, so the effect goes away? So it's just a temporary hive mind? So it can only be a hive mind once in each person?

Interesting side effects can be noted if the subject is a SCP, splitting its double personality like normal, but also splitting its power between the subject, and the second personality, like the case of SCP███ and SCP███.

They've tried with SCPs too?! What the fuck is even going on?!

Addendums:
Alright, so I'm not going to quote anything from the addendums, becauSe they are a complete mess. Grammar is way off, and I dunno what you're even trying to tell me. Like, it for control over a kid or something? And then the new personality was like the imagination of the boy and…What?

As for the second addendum, well…
It throws out your previous containment procedures, for one thing. Shouldn't you have mentioned beforehand that it's forbidden to interact with it now?
Also, what the hell happened in that addendum? Like, a guy touched her, and then a new body appears, but it's fine, since he's not sick?

Overall, this is a complete mess. I think the biggest part of it is your grammar, because I certainly can't figure out what's going on. I'd suggest rewriting, like…All of it? I'm a huge fan of SCPs that affect you mentally, but this was not one of them.

Well, i made some changes about the problems you said.But…
My first language is not english, is Portuguese (Brazil),(I can comunicate without many problems, but never wrote a text this big before xD).. so any language problem i will try to resolve. Thanks!